SEACLID/CORDEX Southeast Asia

Introduction

The Southeast Asia (SEA) region, a region with a population of more than 600 million, is considered as a region of the highest risk of climate change impacts, particularly weather and climate extremes. Southeast Asia has high exposure, low adaptive capacity and high vulnerability to climate related hazards. For a period from 1980 - 2107, Southeast Asia recorded the highest number of disasters (Dagli & Ferrarini 2019). Weather and climate related hazards are expected to increase in future decades as climate continues to warm (IPCC 2021). However, with high uncertainty in mitigation effort in reducing future greenhouse gases (GHG) emission and associated future warming, it is now important to equally emphasize on adaptation measures in increasing climate resilience. This is certainly the case for least developed and developing countries in Southeast Asia where exposure and vulnerability to climate related hazards are higher. The current annual GHG emission stands at 51 GtCO2e. According to the IPCC Special Report 1.5C, for the Paris Agreement's threshold 1.5C warming limit to be achieved, the current level of GHG emission needs to be reduced to the level of 20 - 30 GtCO2e annually by 2030 i.e. roughy about 50% reduction in a short period of about 9 years. The current pledges under the Paris Agreement is not sufficient to limit the warming under 1.5oC target. In fact, under the current pledges the warming is projected to be around 2.5 - 2.8C. The current policies are projected to cause further warming to 2.8 - 3.2C (Our World in Data).

Figure indicating projected warmings according to different emission scenrios and current pledges under the Paris Agreement (Our World in Data)

Countries in Southeast Asia would need to establish National Adaptation Plan (NAP) anddevelop policies to enable adaptation measures to increase climate resilience. Despite different countries may need different requirement to implement NAP, all countries require robust knwlodege on how future climate change change would be affecting the population, their livelihoods, cirtical sectors and what adaptation measures need to be implemented. For robust climate change policy in enabling adaptation, research communities from both climate modelling and VIA need to work closely to ensure robust assessment of risk of climate change impacts.

Figure illustrating how risks of climate change impacts are shaped by future climate hazards, exposure and vulnerability.

For countries to prepare for adaptation measures, high-resolution regional climate change scenarios are elementary requirements for carrying impact assessment studies. However, such impact assessment studies are often limited by the unavailability of latest, freely accessible and high-resolution climate change scenarios. To generate such high-resolution products from coarse general circulation model (GCM) outputs, one requires a regional climate model to "refine" the GCM outputs via a technique known as a dynamical climate downscaling, which is known to be time-consuming and resource-expensive. To provide ranges of uncertainties from different models and future GHG emissions, downscaling exercises must employ multiple GCMs and RCPs. For a single country or a single institution in the region to downscale multiple GCMs and RCPs remains a greate challenge. The SEA region is undoubtedly lagging behind from other regions in regional climate downscaling activities and hence large knowledge gaps exists e.g. as indicated in the IPCC WG1 AR5 for SEA regional assesment of physical basis of climate change. In the interest of countries within the region, regional climate downscaling can be implemented on a task-sharing basis where tasks can be somewhat equally distributed to member countries. This approach reduces the time needed to run the models as well as the computing resource required can be affordable. This is the basis of the establishment of the Southeast Regional Climate Downscaling (SEACLID) Project. SEACLID is the first project of regional climate downscaling in the Southeast Asia region that involves various countries where full cooperation and task-sharing basis are practiced. Prior to the establishment of SEACLID, the Southeast Asia region was included in CORDEX East Asia's domain. However, there was no single country in the Southeast Asia region directly involved in CORDEX East Asia.

Photo: SEARCI's first workshop, VNU Hanoi University of Science, 2-3 August 2012

The SEACLID project is a bottom-up initiative by the scientists from within the Southeast Asia region under the Southeast Asia Regional Climate Initiative (SEARCI), a newly regional collaborative platform in climate related issues which was established during a workshop hosted by the VNU Hanoi University of Science, Vietnam, 2-3 August 2012. Scientists from five countries including Malaysia, Vietnam, Indonesia, the Philippines and Thailand attended this workshop. Prof. Dr. FredolinTangang of the National University of Malaysia was elected as the leader of this initiative. During this workshop, SEACLID project was conceptualized and subsequently a proposal was developed and submitted to the Asian Pacific Network (APN) for Global Research (APN) for possible funding. As to fulfill the APN requirement, two additional countries i.e. Cambodia and Lao PDR, were incorporated into the group.  In May 2013, SEACLID successfully secured an APN funding for its implementation [ARCP2013-17NMY-Tangang, ARCP2014-07CMY-Tangang, ARCP2015-04-CMY-Tangang]. The total approved fund was USD135,000 for a duration of three years starting October 2013. Due to the similarity in concept and its implementation and the need for SEACLID to be streamlined to existing international initiative of regional climate downscaling, SEACLID was later integrated into CORDEX (thanks to the initiave of Dr Gassem R. Asrar, former Director of WCRP for) and became the latest member (14th) in WCRP CORDEX families. The project was subsequently renamed as SEACLID/CORDEX Southeast Asia.

The main objectives of SEACLID/CORDEX Southeast Asia (CORDEX-SEA) includes:

• To downscale a number of CMIP5 GCMs for the Southeast Asia region;
• To generate and disseminate the high-resolution regional climate change scenarios freely via Earth System Grid Federation (ESGF),
• To narrow knowledge gaps related to regional climate change by increasing peer-review scientific and policy-relevant publications;
• To strengthen research capacity and capability, particularly in numerical regional climate modelling, and
• To create a platform for scientists (especially young scientists) within and outside the region to collaborate in issues related to regional climate downscaling.

SEACLID/CORDEX - SEA is a success story. From without much of regional climate downscaling activities in 2012, in a couple of years parternships through CORDEX and funding provided by the APN and co-funders brought Southeast Asia to a region equipped with sufficient climate information and data availability for robust impact assessments to be carried out by VIA community. A total of 11 CMIP5 GCMs have been downscaled using 7 RCMs into CORDEX-SEA domain with a resolution of 25 km (Tangang et al. 2020). These data are archived in the Southeast Asia Regional Climate Change Information System (SARCCIS). SARCCIS is a dataportal established under SEACLID/CORDEX-SEA, an ESGF data node hosted by RUCORE. SEACLID/CORDEX-SEA has advanced scientific knowldege of climate change in the publications of > 20 scientifc papers. Under SEACLID/CORDEX-SEA capacity and capability in regional climate modelling have been advanced with many young scientists graduated with MSc and PhD degrees. Many worksho and training have also been conducated.